Selection of the circuit breaker

Selection of the circuit breaker

Selection of the circuit breaker The selection of the air switch Circuit breaker, full name automatic air circuit breaker, also known as air switch, is a commonly used low-voltage protection appliances, can achieve short circuit, overload and other functions. The circuit breaker is used in the home power supply for the total power protection switch or branch line protection switch. When the residential circuit or household appliances short circuit or overload, it can automatically trip, cut off the power, so as to effectively protect the equipment from damage or prevent accidents. Households generally use two-pole (ie 2P) circuit breakers for total power protection, with a single pole (1P) for branch protection. If the choice of the circuit breaker is too small, the circuit breaker is prone to frequent tripping, causing unnecessary power failure, such as the choice is too large, then the desired protection effect, so the home improvement circuit breaker, the correct choice of rated capacity current size is very important. 10A, 25A, 32A, 50A, 63A, 80A, 100A, etc .; then the general family how to choose or check the total load current of the total value of it? 1, first calculate the value of each branch current ① pure resistive load, such as bulbs, electric heaters, etc. with the specified power directly divided by the voltage that is, Formula I = Power / 220v; Such as 20w bulb, branch current I = 20W / 220 = 0.09A Electric water heaters, electric heaters, rice cookers, electric woks, vacuum cleaners, air conditioners, etc. are resistive loads. Electric water heaters, electric heaters, electric cookers, electric cookers, vacuum cleaners, How to choose a circuit breaker This is a professional technical problem. Briefly said that you can choose from the following 6: 1, first according to the rated voltage selection, the rated voltage to be consistent. 2, the rated current of the circuit breaker is greater than or equal to the rated current of the circuit used. 3, the rated breaking current of the circuit breaker is greater than or equal to the short circuit current of the circuit used. 4, according to environmental conditions, such as altitude, temperature, humidity, choose to meet the requirements of the circuit breaker. 5, according to the quality of the brand selection, cost-effective circuit breakers. 6, the special break off the situation, to check the circuit breaker. However, different loads should use different types of circuit breakers.The principle of air switch selection 1, according to the requirements of the line to protect the circuit breaker to determine the type and form of protection – to determine the use of frame type, device type or flow limit and so on. 2, the rated voltage of the circuit breaker UN should be equal to or greater than the rated voltage of the protected circuit. 3, circuit breaker undervoltage release rated voltage should be equal to the rated voltage of the protected circuit. 4, the rated current of the circuit breaker and the rated current of the overcurrent release shall be greater than or equal to the calculated current of the protected circuit. 5, the circuit breaker limit breaking capacity should be greater than the line of the maximum short-circuit current RMS. 6, the distribution line in the lower and lower circuit breaker protection characteristics should be coordinated with the protection of the lower level should be located in the lower level of protection features and do not intersect. 7, the circuit breaker long delay trip current should be less than the conductor to allow continuous current.